It is, of course, the most agonizing injury known. The thought of it makes the strong tremble and the weak pass out. Its brutality can be unbounded—a loose page will suffice. It is the paper cut.

My thoughts went to the cruelest cut when a friend showed me a particularly vicious one she’d received on her fingertip. Most paper cuts I’d seen or suffered were straight slices less than a centimeter across. Hers was at least twice the normal length and zagged in the middle, as if some invisible assailant decided to twist a miniature knife. In the midst of my horror, I wondered what modern medicine has to say about the paper cut.

Surprisingly little, I discovered. Studies mentioning paper cuts that I found in medical journals were almost uniformly concerned with the possibility of infection, especially by the superscary methicillin-resistant Staphylococcus aureus bug, aka MRSA. A few sources noted that a hemophiliac will not in fact bleed to death from a paper cut, thereby dispelling a piece of playground wisdom widely disseminated among the community of eight-year-old amateur hematologists.

An irony of paper cuts, contends the Wisegeek Web site, is that they are more likely to occur when the paper is high quality. “When glossy sheets of paper are cut very thin, they are uniquely good at causing paper cuts,” the site explains. Grab a ream of tightly bound paper with one interior sheet protruding slightly, and you have a serious weapon on your soon-to-be-bloody hands. “The other papers hold the dislocated paper in position, giving it enough stiffness to cut like a razor’s edge,” Wisegeek says. Which is why there may be a trail of blood leading from the office copier to the desk of whatever unfortunate soul did the good deed of filling up an empty paper tray.

Paper cuts do indeed bring on outsize pain. Fingertips, the most likely site of damage, are loaded with the nerve endings—including the pain-interpreting nociceptors—necessary for the constant exploration of the environment. Take a gander at a cortical homunculus, a representation of how much of the brain is devoted to dealing with signals from individual body parts: I can’t hold a basketball with one hand, but my homunculus could palm a beach ball. So a tiny tip rip gets a disproportionate number of nociceptors, none of which knows the difference between a vacation brochure and a samurai sword.

The fear of a specific kind of paper cut overwhelms me whenever I’m about to send snail mail. In the movie Swimming with Sharks, the cowering assistant to misanthropic film executive Kevin Spacey reaches his breaking point. He ties up the exec and administers facial slices with the edge of an office envelope. Watching this scene instilled such terror that I changed my conventional east-west style of envelope licking, for fear of a tongue slash, to a series of north-south dabs.

The homunculus’s crazy-big tongue supports my decision. It also shows why another fictional entertainment industry giant, Alec Baldwin’s 30 Rock kingpin Jack Donaghy, was probably wasting his time when he took lessons on “how to avoid getting paper cuts while making love in a pile of money.” The legs and torso together take up less brain space than the tongue or fingers.

Also, Benjamins are soft. And soft paper is safer. Wisegeek points out that “newspaper may be the least likely to inflict a paper cut.” I can offer anecdotal evidence in support of that claim. In my first job in journalism—as a paper boy delivering thousands of copies of the New York Post—I did not receive a single paper cut. Then again, the last time the Post contained anything sharp it was still being edited by William Cullen Bryant.

Editors’ note: While opening reader mail just five hours after filing this column, Mirsky suffered a nasty paper cut.

This article was published in print as "The Unkindest Cut."